$\sqrt{81}-4\:x\:5\:+3^3$

$\frac{3}{4}x+\frac{1}{7}x$

$\left(gh\right)^0$

$\log\left(x\right)-\frac{1}{2}\log\left(x+1\right)-\log\:\left(x-1\right)=\log\:\left(\frac{x\sqrt{x+1}}{x^2-1}\right)$

$\left(3\cdot x-9\right)^2$

$8.3\:\frac{1}{2}$

$\lim_{x\to0}\left(\frac{x-8\sin\left(x\right)\cos\left(x\right)}{\tan\left(x\right)-x}\right)$